Numerical analysis of azimuthal rotating spokes in a crossed-field discharge plasma

TL;DR

This paper uses advanced numerical simulations to analyze low-frequency rotating spokes in a cross-field plasma, revealing a stable hyperbolic approach that accurately predicts phase velocity consistent with experimental and theoretical data.

Contribution

It introduces a hyperbolic method for stable electron fluid modeling in plasma simulations, improving convergence and accuracy over traditional drift-diffusion approaches.

Findings

Simulated rotating spokes propagate at 2,500 m/s, matching experimental observations.

The phase velocity aligns with predictions from the gradient drift instability dispersion relation.

The hyperbolic approach enhances numerical stability and convergence in plasma modeling.

Abstract

Low-frequency rotating spokes are obtained in a cross-field discharge plasma using two-dimensional numerical simulations. A particle-fluid hybrid model is used to model the plasma flow in a configuration similar to a Hall thruster. It has been reported that the drift-diffusion approximation for an electron fluid results in an ill-conditioned matrix when solving for the potential because of the differences in the electron mobilities across the magnetic field and in the direction of the E$\times$B drift. In this paper, we employ a hyperbolic approach that enables stable calculation, namely, better iterative convergence of the electron fluid model. Our simulation results show a coherent rotating structure propagating in the E$\times$B direction with a phase velocity of 2,500 m/s, which agrees with experimental data. The phase velocity obtained from the numerical simulations shows good agreement with that predicted by the dispersion relation of the gradient drift instability.